/Engine/Source/Runtime/Core/Public/Serialization/PackageWriter.h
Create theFLargeMemoryWriterto which the Header and Exports are written during the save.
virtual [TUniquePtr](API\Runtime\Core\Templates\TUniquePtr)< [FLargeMemoryWriter](API\Runtime\Core\Serialization\FLargeMemoryWriter) > CreateLinkerArchive ( [FName](API\Runtime\Core\UObject\FName) PackageName, [UObject](API\Runtime\CoreUObject\UObject\UObject) * Asset, uint16 MultiOutputIndex )